ATER (ATIP Error Rate) is the number of erroneous ATIP frames
in proportion to the total number of frames, averaged over 10
seconds. You can see it as C1 errors for ATIP informations : keep
the same drive and change the discs, you will compare the discs'
mastering quality. Keep the same disc and change the drives,
you will compare the drives' wobble and atip detection.